The present invention relates to automotive latching devices and, in particular, to a solenoid device having an alignment compensating latch which is particularly adapted for use with a fuel filler door latch system to inhibit unauthorized access to a fuel tank.
In an effort to inhibit unauthorized access to a vehicle's fuel tank, automobile manufacturers are evaluating various fuel filler door latching systems. Conventionally, latching systems have included the use of a striker bar fixed to the filler door and a latch member ("bolt") mounted to the vehicle body. The latch member engages the striker bar in a "latched" position when the filler door is closed. To release the fuel filler door, the latch member is moved to an "unlatched" position to disengage the striker bar, thereby allowing the fuel filler door to open freely for access to the fuel cap.
As a convenience option, vehicle manufacturers are installing remotely actuated fuel filler door latch release systems. Remotely actuated latching systems permit an occupant within the passenger compartment of the vehicle to open "unlatch" the fuel filler door prior to exiting the vehicle. Typically, remotely actuated latching systems include the use of a linear actuation cable or linkage coupled to the latch member for manually releasing the filler door. In general, a vehicle occupant pulls a release handle located within the passenger compartment to operatively move the latch member out of engagement with the striker bar. Alternatively, many vehicles are now being equipped with electrically actuated release systems. These systems typically include a solenoid device mounted remote from the fuel filler area, and a linkage or actuation cable coupled between a movable solenoid armature and the latch member. Energization of the solenoid moves the armature and, consequently, the latch member to disengage the striker bar.
Because the fuel filler door is a cosmetic "fit and finish" component of an automobile, it must be precisely aligned during assembly. It is common for conventional fuel filler latching mechanisms to require adjustment of the alignment between the latch member and the striker bar following vehicle assembly to ensure that the release system will function properly.
A disadvantage associated with "prior art" solenoid operated fuel filler latching mechanisms is the excessive armature travel ("stroke") required to assure adequate system reliability. Conventional solenoid actuated release systems must generate sufficient armature travel to account for any dimensional and alignment variations associated with the components making up a fuel filler door assembly and latch mechanism. Specifically, the anticipated range of alignment variability between the location of the striker bar and the latch member must be taken into account in determining the amount of armature stroke required. As is known in solenoid design, it is an inherent characteristic that the magnetic attractive force produced by a solenoid device decreases as its armature travel increases. Consequently, to assure adequate movement of the latch member to release the striker bar, it is necessary to provide a relatively large and expensive solenoid to generate the sufficient force output.
Accordingly, it is a primary object of the present invention to overcome the disadvantages of the prior art and to provide an improved solenoid device having means for compensating for variations in the alignment of the striker bar relative to a latching member. In particular, the present invention includes a self-compensating solenoid apparatus operable to minimize the effects of alignment variations between the striker bar and an integral latch member.
In general, this is accomplished by providing a solenoid actuated latch apparatus having a movable pole piece adapted to bias a position compensating guide member to a normally protracted position. The guide member coacts with a latch bolt for aligning the latch bolt with respect to the striker bar to compensate for alignment variations therebetween. In particular, when the striker bar contacts the guide member, the guide member is retracted for producing corresponding movement of the pole piece. In addition, retraction of the guide member also produces corresponding movement of the latch bolt to maintain a desired axial relationship between the latch bolt and the guide member prior to engagement of the latch bolt with the striker bar. In this manner, engagement of the movable guide member with the striker bar acts to compensate for alignment variations between the striker bar and the latch member. The present invention is a compact solenoid assembly having a self-compensating latching components associated therewith. The solenoid assembly can be mounted to a fuel filler housing to define a fuel filler housing assembly which can be readily installed as a sub-assembly into a vehicle.
The self-compensating characteristic of the present invention permits the magnetic attractive force requirement for a solenoid to be predicated on a substantially reduced amount of armature travel. Because alignment variations associated with the striker bar can be compensated for without impacting solenoid armature travel requirements, the travel requirement and therefore, the size of the solenoid can be substantially reduced. In this manner, the overall size, weight, and cost of the solenoid can be reduced.
To release the striker bar, the solenoid assembly of the present invention is energized to move the latch bolt out of engagement with the striker bar. Consequently, the present invention provides increased system reliability, is relatively simple and inexpensive to manufacture, and is convenient for subassembly into a vehicle.
Additional objects, advantages, and features of the present invention will become apparent from a reading of the following detailed description and appended claims, taken in conjunction with the accompanying drawings.